1. Field of the Invention
The present invention generally relates to a backlight module and a liquid crystal display, in particular, to a backlight module adapted for providing uniform surface light source and a liquid crystal display utilizing the backlight module.
2. Description of Related Art
With recent advancement in modern video technology, the tendency of the video device is towards light weight, big size and thin panel. The flat panel display fabricated by the optoelectronic technology and semiconductor process such as the liquid crystal display (LCD), the organic electroluminescent device (OLED) or the plasma display panel (PDP) has become the mainstream of the display device. Most of the cell phone, the digital camera, the digital video camera, the notebook and the desk-top computer utilize the LCD panel as the display screen. The LCD panel doesn't emit light itself so a backlight module is arranged below the LCD panel, to provide the surface light source for the LCD panel. Then, the LCD panel can display image.
FIG. 1 is a three-dimensional view showing a conventional backlight module. As shown in FIG. 1, the backlight module 100 comprises a frame 110, a fixing adhesive tape 12, a reflective plate 130, a light-guiding plate 140 and a light source 150. The fixing adhesive tape 120 is disposed in one side 112 of the frame 110. The reflective plate 130 is disposed in the frame 110. The light-guiding plate 140 having a light incident surface 142 is disposed in the frame 110, and on the reflective plate 130 and the fixing adhesive tape 120. The light source 150 is disposed beside the light incident surface 142 of the light-guiding plate 140. Besides, as shown in FIG. 1, optical films such as a collecting sheet 160 and a diffusion sheet 170 can be sequentially stacked on the light-guiding plate 140.
It should be noted that a prism type light-guiding plate 140 is adapted for enhancing the brightness of the backlight module 100, as shown in the enlarged part of FIG. 1. Because fasteners such as locating protrusions or pared corners may damage the structure of the prism type light-guiding plate 140, therefore, they are not suitable for locating the prism type light-guiding plate 140 in the frame 110. According, the prism type light-guiding plate 140 is generally fixed in the frame 110 by the fixing adhesive tape 120. However, when the prism type light-guiding plate 120 is fixed by using the fixing adhesive tape 120, a gap d1 (as shown in FIG. 2) may be formed between the fixing adhesive tape 120 and the reflective plate 130.
FIG. 2 is a schematic cross-sectional view showing a liquid crystal display which the backlight module shown in FIG. 1 is applied to; the cross-sectional view is drawn along line A-A′. Please refer to FIG. 2, the liquid crystal display 300 comprises the backlight module 100 and a liquid crystal display panel 200. The backlight module 100 is adapted for providing the liquid crystal display panel 200 with a surface light source in order to display. Because the gap d1 is formed between the fixing adhesive tape 120 and the reflective plate 130, the intensity of the light 190 reflected from the frame 110 within the gap d1 is different from that of the light 192 reflected by the reflective plate 130. Accordingly, the backlight module 100 would not be able to provide uniform light source, and a region 202 having non-uniform light intensity is formed in the liquid crystal display panel 180 and is corresponding to the gap d1.